1. FIELD OF THE INVENTION
This invention relates to a method of fire prevention during and after the application of a roof or roof repair requiring flame heating. More especially this invention relates to a method of fire prevention during and after the application of modified bitumen roofing membranes, and the repair of modified bitumen roofs.
Modified bitumen is a general class of asphaltic roofing membrane that has been manufactured and widely used in Europe and the United States for twenty-five years. Modified bitumen membrane consists of a layer of bitumen waterproofing material, modified with plastomers to add strength, and having an embedded reinforcing fabric. The modified bitumen membrane is heat welded by an open flame torch to a contact point which is concurrently flame heated. The contact point, or substratum, is usually a flammable material such as wood, insulation, wood fiber, plywood, tar paper, or the like. The perimeter of the roof is usually surrounded by parapet walls which are considered a continuation of the roof itself. The contact point for parapet walls can include the previously mentioned flammable materials and they also include brick, cinder block and sheet metal flashing. Although these latter materials are not themselves flammable, they tend to collect flammable materials such as leaves, paper, dust, etc.
The open flame torches used for application of modified bitumen roofing membranes, usually fueled with propane, vary from 50,000 BTU hand-held torches to multiple torch machines capable of two million BTUs. The hand-held torch is waved in a side-to-side motion to heat the underside of the modified bitumen membrane for adhesion to the contact point. The multiple head torch machine is pulled backward from an unrolling roll of bitumen membrane to heat the modified bitumen and contact point. These procedures may vary somewhat depending upon the ambient temperature, applicator discretion, different melting points of modified bitumens and different torches.
While heating the modified bitumen the open flame deflects and superheats the contact point and surrounding area. This often causes flammable materials to smolder, glow and catch fire. If the fire is detected by the applicator, he must take the extra time to extinguish the flame. When the smoldering or glow of a possible fire is undetected, it is covered by the roofing membrane and becomes a great hazard. The smoldering glow in wood walls and insulation can last for hours before bursting into flame. The resulting fire is hard to reach on the roof, usually spreads fast and may be very dangerous.
2. The Prior Art
Although modified bitumen membrane has been in use for twenty-five years, fires have been a constant hindrance and safety problem. In spite of this to applicant's knowledge, no method of preventing such fires has been proposed.